package cn.itcast.n8;

import lombok.extern.slf4j.Slf4j;
import sun.util.resources.cldr.ka.LocaleNames_ka;

import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.AbstractQueuedSynchronizer;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;

/**
 * @Author: LDeng
 * @Date: 2021-07-05 14:16
 */

@Slf4j(topic = "c.TestAqs")
public class TestAqs {


}


//自定义锁（不可重入锁）
class MyLock implements Lock {

    //独占锁 同步器类
    class MySync extends AbstractQueuedSynchronizer{
        @Override
        protected boolean tryAcquire(int arg) {
            if(compareAndSetState(0,1)){
                //加锁，并设置owner为当前线程
                setExclusiveOwnerThread(Thread.currentThread());
            }
            return false;
        }


        @Override
        protected boolean tryRelease(int arg) {
            setExclusiveOwnerThread(null);
            setState(0);
            return true;
        }

        @Override//是否持有独占锁
        protected boolean isHeldExclusively() {
            return getState()==1;
        }

        public Condition newCondition(){
            return new ConditionObject();
        }
    }

    private MySync sync=new MySync();

    //加锁， 不成功进入等待队列
    @Override
    public void lock() {
        sync.acquire(1);
    }

    //加锁， 可打断
    @Override
    public void lockInterruptibly() throws InterruptedException {
        sync.acquireInterruptibly(1);
    }

    //尝试加锁，一次
    @Override
    public boolean tryLock() {
        return sync.tryAcquire(1);
    }


    //尝试加锁，带超时时间
    @Override
    public boolean tryLock(long time, TimeUnit unit) throws InterruptedException {
        return sync.tryAcquireNanos(1,unit.toNanos(time));
    }

    //解锁
    @Override
    public void unlock() {
         sync.release(1);
    }

    //创建条件变量
    @Override
    public Condition newCondition() {
        return sync.newCondition();
    }
}